Sandwich assays details

The immunometric-type assay has also been adapted for use with nonisotopic labels and is typically carried out in a heterogeneous format in which the antibody is immobilized on a solid support, such as a microtiter dish, membrane, or collection of beads. The canonical clinical immunoassay format in toady s laboratories is the enzyme-linked immunosorbent sandwich assay, which employs two antibodies, one to capture the analyte and the other to detect and quantify it. More details of the principles of these and other immunoassay techniques are given elsewhere in this encyclopedia. 

The bead-based ECIAs developed thus far in our labs have used polystyrene culture tubes to hold the beads. Sandwich enzyme immunoassay was chosen for the assay format, and Figure 13 gives a schematic representation of the experimental setup. The details of the assay procedure including the various buffers, the sample volumes, and incubation times can be found elsewhere [48]. 

The detection of type E C botulinum complex using the fiberoptic biosensor was accomplished using a two-step sandwich immunoassay. The assay involved (1) the incubation of antibody bound fibers in a solution of type E complex followed by (2) signal collection upon incubation of the resulting complex bound fibers in a fluorescently labeled antibody solution. The procedures and fundamentals involved are discussed below in detail. 

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